ORCID ID

Contact details

Additional identifiers

EudraCT number

ClinicalTrials.gov number

Protocol/serial number

N/A

Study information

Scientific title

Acronym

Study hypothesis

Amphetamine abuse and dependence represents a major public health problem with growing psychiatric, social and economic consequences. The total number of amphetamine abusers world-wide is estimated to 34 million, a figure larger than the combined number of cocaine and heroin abusers. In Sweden, amphetamine is the most commonly abused substance after cannabis and alcohol. To date, the development of an efficacious pharmacotherapy has remained elusive, although the neurobiological effects of amphetamine have been investigated extensively.

Hypothesis:To investigate the effect of chronic treatment of naltrexone on amphetamine dependence. With the specific aim of assessing the efficacy of naltrexone in comparison to placebo in increasing weeks of abstinence in amphetamine dependent patients.

Ethics approval

Ethics approval received from:1. The Regional Ethical Review Board in Stockholm on the 6th May 2002 (ref: 03-132) 2. The Swedish Medical Products Agency on the 20th August 2002 (ref: 151:2002/26412)

The trial was conducted in accordance with Good Clinical Practice (ICHGCP, 1996) and the Declaration of Helsinki.

Study design

This was a randomised double-blind placebo-controlled 12 week study.

Primary study design

Interventional

Secondary study design

Randomised controlled trial

Trial setting

Hospitals

Trial type

Treatment

Patient information sheet

Condition

Amphetamine abuse and dependence

Intervention

This was a randomised, double blind, single-site placebo-controlled trial of Naltrexone (NTX) for amphetamine dependence. Post the lead-in period, 80 patients were randomised to either placebo or NTX treatment for 12 weeks. Patients were asked to attend the clinic twice weekly. On the first weekly visit they met with a research nurse, left supervised urine samples, collected the weekly medication (50 mg naltrexone or an identical placebo in blisters of 7 each), dispensed by the research nurse and filled out questionnaires. On the second weekly visit they received relapse prevention therapy from a licensed psychologist and in addition left supervised urine samples. All urine samples were screened for amphetamine, benzodiazepines, cannabis, cocaine (benzoylecgonine), dextropropoxyphen and opiates. Weekly assessments also included craving measures, self reports of drug use and monitoring of adverse events.

Intervention type

Drug

Phase

Not Specified

Drug names

Naltrexone

Primary outcome measure

The primary outcome measure of the study was abstinence from amphetamine use, as measured by negative amphetamine urine samples during 12 weeks of treatment (maximum of 24 samples). All missing urine samples were imputed as positive in the analysis. The primary analysis was carried out according to the Intention-To-Treat (ITT) approach.

Secondary outcome measures

Secondary outcomes measures included the following:1. Self reported use of amphetamine (as measured by Timeline Follow Back)2. Self reported use of alcohol and other drugs of abuse (as measured by Timeline Follow Back)3. Compliance to treatment, defined as:3.1. 16/24 urine samples3.2. Medication compliance, detected by the presence of 6-β-naltrexol in the urine 3.3. Pill counts4. Craving for amphetamine, measured by the amphetamine craving scale5. Adverse events, monitored by the study physician and weekly self-report by patient

All secondary outcome measures were evaluated on a weekly basis.

Overall trial start date

10/01/2003

Overall trial end date

23/06/2005

Reason abandoned (if study stopped)

Eligibility

Participant inclusion criteria

1. Adult male or female between 18 to 65 years2. Written, informed consent to participate3. Address and telephone in the Stockholm metropolitan area where the participant can be reached4. Amphetamine dependence according to Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) criteria5. Having used amphetamine on a minimum of 12 occasions during the 12 weeks prior to screening 6. Two consecutive urine tests with no traces of amphetamine following screening

Participant type

Patient

Age group

Adult

Gender

Both

Target number of participants

80

Participant exclusion criteria

1. Opiate abuse or dependence2. Use of any opiate preparation (legal or illicit) during 30 days prior to screening3. Presence of opiates in urine at screening4. Other mental disorders than substance abuse/dependence considered to be severe and requiring treatment (dementia, severe depression with suicidal ideation, acute psychotic symptoms, schizophrenia - concurrent pharmacological treatment for depression, and mild psychotic symptoms such as paranoid ideation or other forms of milder delusions for which the patient has some degree of insight do not constitute exclusion criteria)5. Ongoing treatment with benzodiazepines6. Acute withdrawal symptoms at screening, irrespective of cause7. Serious somatic disorder (e.g., cancer, moderate to severe hypertension, advanced atherosclerosis, liver cirrhosis, or other disorders considered to be a risk)8. Known hypersensitivity to naltrexone